HVAC control with utility time of day pricing support

ABSTRACT

The present disclosure provides a method for operating a utility-powered HVAC system for conditioning inside air of a building. In an illustrative but non-limiting example, a nominal schedule is maintained by a local HVAC controller, where the nominal schedule has a number of days and one or more time periods for each of at least some of the days. The nominal schedule also has at least one setpoint associated with each of the time periods. The local HVAC controller is configured to accept manual input from a user via a user interface. The manual input may include accepting entry of a utility pricing schedule that corresponds to scheduled price changes of a utility. The utility pricing schedule may include at least one enhanced pricing time period. Entry of at least one utility price level setpoint offset may also be accepted to correspond to each of the enhanced pricing time periods. The nominal schedule may then be modified or overridden to include the utility pricing schedule, resulting in a utility pricing operating schedule. One or more HVAC units may then be controlled by the local HVAC controller in accordance with the utility pricing operating schedule.

TECHNICAL FIELD

The disclosure pertains generally to HVAC control, and moreparticularly, to HVAC control with utility time of day pricing support.

BACKGROUND

Heating, ventilation, and/or air conditioning (HVAC) systems are oftenused to control the comfort level within a building or other structure.Many HVAC systems include a controller that activates and deactivatesone or more HVAC units or components of the HVAC system to affect andcontrol one or more environmental conditions within the building. Theseenvironmental conditions can include, but are not limited to,temperature, humidity, and/or ventilation. In many cases, such an HVACcontroller may include, or have access to, one or more sensors, and mayuse parameters provided by the one or more sensors to control the one ormore HVAC components to achieve desired programmed or set environmentalconditions.

An HVAC controller may be equipped with a user interface that allows auser to monitor and adjust the environmental conditions at one or morelocations within the building. With more modern designs, the interfacetypically includes a display panel, such as a liquid crystal displaypanel, inset within a housing that contains a microprocessor as well asother components of the HVAC controller. In some designs, the userinterface may permit the user to program the controller to activate on acertain schedule determined by the user. For example, the interface mayinclude a routine that permits the user to change the temperature at oneor more times during a particular day and/or group of days. Such aprogrammable schedule may help reduce energy consumption of the HVACsystem by changing the setpoint to an energy saving set back temperatureduring certain times, such as when the building or space is expected tobe unoccupied or when the occupants are expected to be sleeping.

Energy is supplied to most HVAC systems by one or more utilities, suchas an electric utility and/or a gas utility. During peak demand periods,such as during hot summer days, such utilities may vary the rates thatthey charge for energy. Customers may wish to modify their energyconsumption in response to these varying rates in order to reduce theirenergy bills. What would be desirable, therefore, is a new HVACcontroller that can help customers modify their energy consumptionduring peak or anticipated peak demand periods.

SUMMARY

The disclosure relates generally to Heating, Ventilation, and AirConditioning (HVAC) control, and more particularly, to HVAC control withutility time of day pricing support.

In some instances, control of an HVAC system may be modified based uponmanually-entered utility pricing schedule information. In anillustrative but non-limiting example, a nominal schedule may bemaintained in a memory of a local HVAC controller, where the nominalschedule has a number of days and one or more time periods for each ofat least some of the days. The nominal schedule may also have at leastone setpoint associated with each of the time periods. Manual input maybe received via a user interface of the local HVAC controller. Themanual input may include accepting entry of a utility pricing schedulethat corresponds to scheduled price changes of a utility. The utilitypricing schedule may include at least one enhanced pricing time period.Entry of at least one utility price level setpoint offset may also beaccepted to correspond to each of the enhanced pricing time periods. Thenominal schedule may then be modified or overridden to include theutility pricing schedule, resulting in a utility pricing operatingschedule. One or more HVAC units may then be controlled by the localHVAC controller in accordance with the utility pricing operatingschedule.

The above summary is not intended to describe each and every disclosedillustrative example or every implementation of the disclosure. TheDescription that follows more particularly exemplifies variousillustrative embodiments.

BRIEF DESCRIPTION OF THE FIGURES

The following description should be read with reference to the drawings.The drawings, which are not necessarily to scale, depict selectedillustrative embodiments and are not intended to limit the scope of thedisclosure. The disclosure may be more completely understood inconsideration of the following description of various illustrativeembodiments in connection with the accompanying drawings, in which:

FIG. 1 is a schematic diagram showing an illustrative HVAC system 10 forconditioning the inside air of a building;

FIG. 2 is a flow diagram of an illustrative method for operating autility-powered HVAC system including accepting entry via manual inputof a utility pricing schedule;

FIG. 3 shows an illustrative example of an HVAC controller that may beused in an HVAC system like that of FIG. 1 and that may be used topractice the method of FIG. 2;

FIG. 4 shows the illustrative HVAC controller of FIG. 3 configured toallow a user to disable or enable a utility pricing operating schedule;

FIG. 5 shows the illustrative HVAC controller of FIG. 3 querying whethercooling temperatures are to be adjusted based on a utility pricingschedule;

FIG. 6 shows the illustrative HVAC controller of FIG. 3 querying whetherdifferent seasonal pricing exists for a utility pricing schedule.

FIG. 7 shows the illustrative HVAC controller of FIG. 3 configured toallow entry of a number of utility price levels;

FIG. 8 shows the illustrative HVAC controller of FIG. 3 configured forentry of a utility pricing level setpoint;

FIG. 9 shows the illustrative HVAC controller of FIG. 3 configured toaccept entry of a seasonal start date of a utility pricing schedule;

FIG. 10 shows the illustrative HVAC controller of FIG. 3 configured toaccept selection of days of the week for inclusion in a group of daysfor a utility pricing schedule;

FIG. 11 shows the illustrative HVAC controller of FIG. 3 queryingwhether there are any utility price level changes during a day;

FIG. 12 shows the illustrative HVAC controller of FIG. 3 querying forwhen a first price change is to occur;

FIG. 13 shows the illustrative HVAC controller of FIG. 3 showing thecurrently set temperature setpoint limits for various price levels;

FIG. 14 is a flow diagram of another illustrative method for operating autility-powered HVAC system including accepting entry via manual inputof a utility pricing schedule;

FIG. 15 shows another illustrative HVAC controller that may be used inan HVAC system like that of FIG. 1, configured in a nominal schedulereview/edit mode;

FIG. 16 shows the illustrative HVAC controller of FIG. 15 displayingheating and cooling setpoints of a nominal schedule in a graphicalformat;

FIG. 17 shows the illustrative HVAC controller of FIG. 15 configured toallow entry of a utility price level setpoint offset;

FIG. 18 shows the illustrative HVAC controller of FIG. 15 displaying asummary of parameters for an enhanced pricing time period;

FIG. 19 shows the illustrative HVAC controller of FIG. 15 displayingheating and cooling operating setpoints of a utility pricing operatingschedule in a graphical format;

FIG. 20 shows another illustrative HVAC controller displaying heatingand cooling operating setpoints of a utility pricing operating schedulein a graphical format; and

FIG. 21 is a flow diagram of another illustrative method for operating autility-powered HVAC system including predicting a Critical Peak Pricingevent.

DESCRIPTION

The following description should be read with reference to the drawings,in which like elements in different drawings are numbered in likefashion. The drawings, which are not necessarily to scale, depictselected illustrative embodiments and are not intended to limit thescope of the invention. Although examples of construction, dimensions,and materials are illustrated for the various elements, those skilled inthe art will recognize that many of the examples provided have suitablealternatives that may be utilized.

FIG. 1 is a schematic diagram showing an illustrative HVAC system 10 forconditioning the inside air of a building. The methods and devices ofthe present disclosure may be practiced with HVAC system 10 and/or aspart of HVAC system 10, but they are not limited to HVAC systems. It iscontemplated that the methods and devices of the present disclosure maybe practiced with other systems, such as water heating systems, lightingsystems, manufacturing systems, sprinkler systems, etc. For convenience,an HVAC system 10 is used as an example below.

The illustrative HVAC system 10 of FIG. 1 includes an HVAC controller12, which may be a thermostat, and may be configured to interact withand control HVAC equipment 14. HVAC controller 12 may be a local HVACcontroller, located in the building that is conditioned by the HVACequipment 14, or in close proximity to the building, such as within acomplex of neighboring buildings. HVAC equipment 14 may include, forexample, one or more of cooling unit 16, heating unit 18 and/orventilation unit 20. HVAC equipment 14 may include other units such as ahumidifier unit, a dehumidifier unit, a UV filter unit and/or any othersuitable HVAC unit. In some cases, cooling unit 16 and heating unit 18may, for example, be combined in a forced air system, or perhaps a heatpump system, particularly in residential and/or light commercialapplications. In other cases, one or more of cooling unit 16, heatingunit 18 and/or ventilation unit 20 may be distinct systems controlled,either directly or indirectly, by HVAC controller 12. In some instances,it is contemplated that HVAC controller 12 may represent two or moredistinct controllers, each controlling different equipment within HVACequipment 14, and/or different zones within a structure.

HVAC controller 12 may include any suitable components related toeffecting control of the HVAC system 10. For example, HVAC controller 12may include a user interface 32. The user interface 32 may include oneor more displays and/or buttons that a user may interact with. In someinstances, a touchscreen display may be provided. In the illustrativeembodiment, HVAC controller 12 includes a processor 34, which may be amicroprocessor, and a memory 36 which may be used to store anyappropriate information such as HVAC control routines or code,historical performance data, HVAC system parameters, one or moreprogrammable schedules for changing HVAC system parameters over time,and so on. HVAC system parameters may include setpoints for heating,cooling, humidity, etc., modes for ventilation equipment, fan settings,and the like.

As shown, HVAC controller 12 may include one or more sensors, such as aninternal sensor 38 located within a housing 42 of the HVAC controller12, and/or external sensors 40, which may be located external to thecontroller housing 42. The external sensors 40 may be within thebuilding and/or outside the building, as desired. HVAC controller 12 mayinclude one or more outputs 44 configured to issue operation commands toHVAC equipment 14 and units 16, 18, 20.

One or more utilities 22 may provide energy to the HVAC system 10,including HVAC equipment 14. The utility or utilities 22 may supply asource of energy such as electricity, natural gas, hot water, steam,and/or any other suitable sources of energy. In order to help reducepeak loads, utilities are increasingly employing variable pricingschemes. Any number of pricing (rate) schemes may be employed. Forexample, energy rates may be raised during an enhanced pricing timeperiod during the day compared to at night, due to higher anticipateddemand for industrial and commercial use and/or greater demand forcooling during daylight hours. Any appropriate number of rate changesmay be made during a day, such as a mid-tier or mid-peak rate becomingeffective at the start of the work day, then a higher-tier orhigher-peak rate becoming effective for the greatest temperature periodlater in the day when air conditioning loads are usually highest, thenreturning to a non-peak rate after the work day ends. In somearrangements, enhanced pricing time periods may recur on a daily basis,or they may recur daily within a group of days such as weekdays, withdifferent rate schedules being effective on other groups of days such asweekends. In some cases, enhanced pricing time periods of a utility mayrecur on a weekly basis.

Schedules for recurrences of enhanced pricing time periods may vary overlonger time intervals, such as between seasons. For example, a summerschedule for weekly recurrences of enhanced pricing time periods may bein force during warmer months of the year, and a different winterschedule may be in effect for colder months.

Utilities may plan and communicate schedules for rate/price changes wellin advance of the dates for such changes. For example, summer and winterenhanced pricing rate schedules may be determined long before thein-force dates for the schedules. In other situations, enhanced pricingtime periods may be declared and/or scheduled on shorter time scales,such as in response to a heat wave or a cold snap (periods of relativelyextreme environmental temperatures), or even due to an unforeseen causesuch as failure of a power generation facility or an internationalcrisis that constrains energy supplies. In some situations a utility mayenact an enhanced pricing time period of Critical Peak Pricing (CPP)with short notice (for example announcing a CPP event one day inadvance), for example in response to actual or anticipated very highdemand for energy.

In response to higher rates during enhanced pricing time periods,customers may desire to curtail energy consumption (and hence, demand onthe utility) relative to consumption during periods of normal or nominalpricing. This may be accomplished by, for example, temporarily settingless comfortable setpoints. Generally speaking, a demand-side responseto enhanced pricing may be achieved in a number of ways. A homeownerwith a simple non-programmable thermostat may manually adjust thethermostat setpoint in response to rate changes. This approach may berelatively labor intensive and require substantial diligence on the partof the homeowner. In a more sophisticated approach, a local HVACcontroller such as a thermostat may be configured to receive automatedsignals from a utility (such as via a wired and/or radio-frequencycommunication link) that communicate enhanced pricing information, andthe HVAC controller may be configured to adjust HVAC system operation ina predetermined response to price changes without the need for immediateuser action and/or awareness. Aspects of such a system are disclosed in,for example, U.S. Pat. No. 6,574,581, “PROFILE BASED METHOD FOR DERIVINGA TEMPERATURE SETPOINT USING A ‘DELTA’ BASED ON CROSS-INDEXING ARECEIVED PRICE-POINT LEVEL SIGNAL,” Bohrer, et al., which is herebyincorporated by reference in its entirety.

In one illustrative embodiment, the present disclosure provides methodsand devices that assist utility customers in modifying HVAC systemoperation and energy consumption in view of rates changes of utilitiesduring enhanced pricing time periods, without necessarily requiring anautomated communication link between a utility and the HVAC systemcontroller. In some instances, methods and devices are described thatallow for manual entry of pricing schedule information into an HVACcontroller. In other instances, methods and devices are described thatallow an HVAC controller to predict Critical Peak Pricing (CPP) events,and control an HVAC system to modify energy consumption during thepredicted CPP event time periods.

FIG. 2 is a flow diagram of an illustrative method 200 for operating autility-powered HVAC system, such as system 10 of FIG. 1. In block 202 alocal HVAC controller may maintain in its memory a nominal schedule thatis used to control the HVAC system during non-enhanced pricing periods.The nominal schedule may represent the normal programmable schedule of aprogrammable thermostat. The nominal schedule may, for example, be a 7day programmable schedule (where each of the seven days of the week canhave a separate schedule), a 5-2 programmable schedule (where the fiveweek days have a common schedule, and the two weekend days have a commonschedule), or any other schedule.

In some cases, the nominal schedule may have a number of days and one ormore time periods for each of at least some of the days. In someinstances, the nominal schedule may include a “sleep,” a “wake,” a“leave,” and a “return” time period for each of the days of a week. Thenominal schedule may have at least one setpoint associated with each ofthe one or more time periods. The nominal schedule may be maintained inthe local HVAC controller's memory, and typically may be modified by anend user. The nominal schedule may be programmed using an interface suchas one of those disclosed in U.S. Pat. No. 7,114,554, “CONTROLLERINTERFACE WITH MULTIPLE DAY PROGRAMMING,” Bergman et al., which ishereby incorporated by reference in its entirety.

Method 200 includes receiving manual input via the user interface of thelocal HVAC controller. At block 204, it includes accepting entry of autility pricing schedule that corresponds to scheduled price changes ofa utility, including at least one enhanced pricing time period. In someillustrative embodiments, the utility pricing schedule is provided tothe user by the utility. For example, the utility pricing schedule maybe provided along with a monthly statement/bill, published in anewspaper, sent via electronic messaging such as in an email message ortext message, made available on a website, and so on. In someillustrative embodiments, the utility pricing schedule may include atleast one recurring enhanced pricing time period, which may recurweekly. In some illustrative embodiments, the utility pricing schedulemay include at least two seasons, and enhanced pricing time periods maycorrespond to one of the seasons. At block 206, method 200 includesaccepting entry of utility price level setpoints to correspond to eachof the enhanced pricing time periods of block 204. Such setpoints may bechosen with the goal of reducing energy consumption (relative to thenominal schedule) during an enhanced pricing time period, often at theexpense of comfort. More than one utility price level setpoint may beentered for each enhanced pricing time period. For example, there may betwo, one for cooling and one for heating. In some illustrativeembodiments, further setpoints may be entered. For example, differentutility price level setpoints may be entered depending on whether anenhanced pricing time period occurs during an occupied period vs. anunoccupied period of the nominal schedule. Aspects of user interfacesthat may be used to accept entry via manual input from a user of utilitypricing schedules and utility price level setpoints are described infurther detail elsewhere herein. Such disclosed user interface elementsmay be considered as extensions of the method 200 of FIG. 2.

Method 200 further includes at block 208, modifying or overriding thenominal schedule to include the utility pricing schedule entered atblock 204 to result in a utility pricing operating schedule. In someillustrative embodiments, the utility pricing operating schedule mayinclude time periods of the nominal schedule and setpoints associatedwith the time periods of the nominal schedule, except that duringenhanced pricing time periods of the utility pricing schedule entered atblock 204, during which the utility price level setpoints correspondingto the enhanced pricing time periods are in effect. At any given time,there may be only one setpoint in effect, which may be referred to as anoperating setpoint, depending on the current mode (e.g., heating orcooling), season, time period, utility price level, and/or any otherrelevant HVAC or utility parameter.

In some illustrative embodiments, the step 208 of modifying oroverriding the nominal schedule to include the utility pricing schedulemay be performed such that the current operating setpoint at any orevery given time during each of the enhanced pricing time periods ischosen to result in greatest economy, consistent with the current mode(heating or cooling) of the HVAC system. This may result in the currentoperating setpoint being either the utility pricing level setpoint forthe current enhanced pricing time period, or the setpoint of the nominalschedule, whichever is most economical. The following non-limitingexample may elucidate this setpoint selection condition: During thecooling season, an enhanced pricing time period from 8:00 am to 5:00 pmhas a utility price level setpoint of 82° F. Prior to 8:00 am, thenominal “wake” time period setpoint is 78° F., so prior to 8:00 am, thecurrent operating setpoint is 78° F. At 8:00 am, the enhanced pricingtime period commences, and the current operating setpoint changes to theutility price level setpoint of 82° F., which is more economical than78° F. At 8:30 am, the nominal schedule switches from “wake” to “leave,”for which the nominal setpoint is 85° F. Thus, at 8:30 am, the currentoperating setpoint changes to the nominal “leave” setpoint of 85° F.,which is more economical than the utility price level setpoint of 82° F.of the current enhanced pricing time period. At 4:00 pm, the nominalschedule switches from “leave” to “return,” for which the nominalsetpoint is 78° F. Now the utility price level setpoint of 82° F., beingmore economical than 78° F., is the current operating setpoint. At 5:00pm, when the enhanced pricing time period ends, the nominal “return”setpoint of 78° F. becomes the current operating setpoint.

The immediately preceding example also illustrates a procedure fordetermining current operating setpoints that may be practiced in someillustrative embodiments. At every start time of either a time period ofthe nominal schedule or a enhanced pricing time period, a comparison maybe made between the setpoint of the current time period of the nominalschedule (for the current mode, either heating or cooling) and theutility price level setpoint (heating or cooling) corresponding to thecurrent enhanced pricing time period. From that comparison, the mosteconomical setpoint is selected as the current operating setpoint atthat start time. Note that in this method, the utility price level“setpoints” may also be regarded as “setpoint limits,” in that theyprovide a limit to how much cooling or heating will be provided duringenhanced pricing time periods.

At block 210, the method 200 includes controlling one or more HVAC unitsof the HVAC system with the local HVAC controller in accordance with theutility pricing operating schedule of block 208.

In some illustrative embodiments of a method, like method 200 foroperating a utility-powered HVAC system, each schedule price change of autility may be associated with a utility price level, such as Off-Peak,Mid-Peak, High-Peak, etc., such that each enhanced pricing time periodhas an associated or corresponding enhanced utility price level (andnon-enhanced pricing time periods may correspond to, for example, anOff-Peak utility price level). Furthermore, at least one utility pricelevel setpoint may be entered, defined, or otherwise set to associatewith or correspond to each of the utility price levels. For example, acooling utility price level setpoint of 85° F. and a heating utilityprice level setpoint of 62° F. may be entered and associated withMid-Peak pricing, and setpoints of 90° F. (cooling) and 57° F. (heating)may be entered and associated with High-Peak pricing.

FIGS. 3-13 show an illustrative but non-limiting example of an HVACcontroller 300 that may be similar to HVAC controller 12 of FIG. 1. HVACcontroller 300, which may be a thermostat, may be used to practicemethods of the present disclosure, including method 200 of FIG. 2,and/or other appropriate methods. Furthermore, descriptions herein ofuser interface elements of HVAC controller 300 may be considered toextend method 200 and other methods of the present disclosure where theyare compatible.

As shown, HVAC controller 300 may include a housing 302 and a display304. Display 304 may be a touchscreen display, and it may be a liquidcrystal display (LCD), although neither of these are required. FIG. 3shows HVAC controller 300 with a default “home” screen presented ondisplay 304. Buttons, such as HOME button 306 and FAN button 308, may beshown on touchscreen display 304. In some other illustrativeembodiments, an HVAC controller may include one or more physicalbuttons, in some cases associated with labels on a display (as withso-called “soft” buttons), and/or in some cases with dedicatedfunctions. More generally, it is contemplated that any suitable userinterface may be used, as desired.

FIG. 4 shows the illustrative HVAC controller of FIG. 3 configured toallow a user to disable or enable a utility pricing operating schedule,such as the utility pricing operating schedule of method 200. Whendisabled, the HVAC controller 300 may control one or more HVAC units ofan HVAC system in accordance with the nominal schedule of method 200.When enabled, the HVAC controller 300 may control one or more HVAC unitsof an HVAC system in accordance with the utility pricing operatingschedule of method 200.

When the use of a utility pricing operating schedule is enables via thescreen shown in FIG. 4, the user interface may follow by prompting andallowing entry of other parameters relating to the use of the utilitypricing operating schedule. For example, if the user selects the “Next”button in FIG. 4, the HVAC controller 300 may advance to the screenshown in FIG. 5. FIG. 5 shows the illustrative HVAC controller 300querying whether cooling temperatures are to be adjusted based on autility pricing schedule. The user interface may similarly allow a userto select whether heating temperatures are to be adjusted based on autility pricing schedule (not shown). Subsequent prompts by and entriesinto the user interface may be scripted based upon user inputs, such asin response to these and other queries. FIG. 6 shows another query thatmay allow the user interface to tailor later prompts to a particularutility scheduling scenario, in this case determining whether differentseasonal pricing exists for a utility pricing schedule.

FIG. 7 shows the user interface configured to allow entry of a number ofutility price levels or tiers in a utility pricing schedule. A utilitypricing schedule may have two (for example, Off-Peak and High Peak),three (Off-Peak, Mid-Peak, and High-Peak, as shown), four (Off-Peak,Low-Peak, Mid-Peak, and High-Peak), or any other appropriate number ofutility price levels. In FIG. 8, the user interface is shown configuredfor entry or setting of a utility pricing level setpoint. In the caseshown, a cooling setpoint is being entered to correspond to or associatewith the Mid-Peak utility price level, and accordingly, corresponds toor is associated with enhanced pricing time periods associated with theMid-Peak utility price level. Similar user interface displays may beused for entry or setting of heating setpoints, and for other utilityprice levels (e.g., Low-Peak and High-Peak). In some illustrativeembodiments, other appropriate HVAC parameters may be entered andassociated with utility pricing levels, such as humidity setpoints, fansettings, etc.

In FIG. 9, the user interface is shown configured to accept entry of aseasonal start date of a utility pricing schedule. A similar userinterface may be used to accept entry of other relevant dates for autility pricing schedule. In FIG. 10, the user interface is shownconfigured to accept selection of days of the week for inclusion in agroup of days, where enhanced pricing time periods will recur each dayof the group of days, and also weekly on those days during the seasonthe enhanced pricing time periods are associated with or correspond to(in this case, Summer).

FIG. 11 shows the user interface querying whether there are any utilityprice level changes (from a nominal Off-Peak price level) during a day.After selection of “Yes,” the user interface moves on, as shown in FIG.12, to allow entry of the time of the first scheduled price change andthe utility price level at that time. After this entry is completed, theuser interface may query whether there is a subsequent utility pricelevel change (similarly to that shown in FIG. 11), and if so, allowentry of the time of the subsequent price change and the utility pricelevel at that time (similarly to that shown in FIG. 12). This processmay repeat until all utility price level changes during the day havebeen entered.

After the utility price level changes for the days in a group of daysselected in FIG. 10 have been entered, the user interface may allow auser to schedule utility price level changes for other days that mayform one or more other groups of days, using the same or similar userinterface elements shown in FIGS. 10-12, and also for days and/or groupsof days during other seasons. The user interface may also allow reviewof a utility pricing schedule. FIG. 13 shows a screen from which a usermay review and/or edit utility pricing schedule and utility price levelsetpoints.

Other user interface arrangements are possible. For example, after entryof a scheduled price change as in FIG. 12, rather than querying whetherthere is a subsequent utility price level change to enter, the userinterface may be configured such that it queries for the total number ofprice changes per day at the outset before it accepts entry ofparameters for any of the scheduled price changes. After accepting entryof the total number of price changes, the user interface could thenprompt for and accept entry of the first price change, second pricechange, etc. Many user interface variations are contemplated for entryof utility price schedules.

In some illustrative embodiments, the utility pricing operating schedulemay only include time periods and setpoints defined either in thenominal schedule or those entered as part of a utility pricing schedule,such as in blocks 204 and 206 of method 200. However, in someillustrative embodiments, the utility pricing operating schedule mayinclude time periods and setpoints other than those in the nominalschedule or those entered in blocks 204 and 206, if desired. In someillustrative embodiments, for example, a utility pricing operatingschedule may include a pre-cooling time period (in a season or on a daywhen HVAC cooling is desired; analogously, a pre-heating time period forwhen HVAC heating is desired). A pre-cooling time period may bescheduled before an enhanced pricing time period, when rates are lowerthan during the subsequent enhanced pricing time period, and in somecases, may include a cooler setpoint than normally would becontrolled-to (at that time) according to the nominal schedule. The useof pre-cooling may allow greater comfort to be achieved during enhancedpricing time periods while still reducing energy consumption during theenhanced pricing time periods. An HVAC controller such as HVACcontroller 12 of FIG. 1 may be configured to incorporate pre-coolinginto a utility pricing operating schedule. In some cases, pre-coolingmay be offered as an option that is selectable by, for example, an enduser or an HVAC technician. Parameters for pre-cooling may be selectedor otherwise determined in any suitable way. For example, parameters forpre-cooling may be user selectable via the user interface. Suchparameters may include pre-cooling temperature limits or bounds, timeparameters for pre-cooling time periods, and/or any other appropriateparameters. In some illustrative embodiments, an end user may simplyenter a preference whether or not to use pre-cooling, and if pre-coolingis desired, the HVAC controller may be configured to add one or morepre-cooling time periods to a utility pricing operating schedule withoutfurther user input.

The present disclosure contemplates additional ways for obtainingutility pricing operating schedules from modification of nominalschedules. For example, FIG. 14 is a flow diagram of anotherillustrative method 400 for operating a utility-powered HVAC system,including accepting entry via manual input of a utility pricingschedule. Method 400 is similar in many ways to method 200 of FIG. 2,and substantial portions of the description of method 200 are relevantto method 400. These include the discussions regarding maintaining anominal schedule in memory of an HVAC controller at 202 and 402, andaccepting entry of a utility pricing schedule at 204 and 404.

Method 400 differs from method 200 at block 406, where method 400includes accepting entry of utility price level setpoint offsets thatcorrespond to the enhanced pricing time periods entered at step 404.Generally, setpoint offsets may be combined with (added to or subtractedfrom) a first setpoint to result in a second setpoint. At block 408,setpoint offsets entered at block 406 may be used in the step ofmodifying or overlaying the nominal schedule to include the setpointoffsets, resulting in a utility pricing operating schedule.

In some illustrative embodiments, operating setpoints for a utilitypricing operating schedule may be obtained by the following method: Whenthere is no enhanced pricing time period in effect, a setpoint of thecurrent time period of the nominal schedule may be used as the operatingsetpoint. During an enhanced pricing time period (e.g. when the currenttime period of the nominal schedule overlaps with the enhanced pricingtime period), a utility price level setpoint offset may be added to thecurrent setpoint of the nominal schedule, resulting in a new operatingsetpoint. To further elucidate this method, an example is discussedelsewhere herein in connection with FIGS. 15-19. Method 400 continues atblock 410 by controlling one or more HVAC units with the local HVACcontroller in accordance with the utility pricing operating schedule.

FIGS. 15-19 show an illustrative but non-limiting example of an HVACcontroller 500. HVAC controller 500, which may be a thermostat, may beused to practice methods of the present disclosure, including method 400of FIG. 14, and/or other appropriate methods. HVAC controller 500 may beessentially the same as HVAC controller 300 of FIGS. 3-13, and may beable to practice method 200 of FIG. 2 as well as method 400 of FIG. 4,if desired. Furthermore, either of HVAC controllers 300 and 500 may bereconfigurable to practice different or new methods, such as via asoftware update, software activation, or any other suitablereconfiguration method.

FIG. 15 shows the user interface of HVAC controller 500 configured in anominal schedule review and edit mode, as may be practiced in an HVACcontrol method of the present disclosure. HVAC parameters for WAKE,LEAVE, RETURN, and SLEEP time periods are shown. FIG. 16 shows the userinterface displaying heating (bottom trace 502) and cooling (top trace504) setpoints for the time periods of FIG. 15 graphically in a 24 hourtime interval.

FIGS. 17-19 particularly illustrate aspects of method 400 of FIG. 14.For example, FIG. 17 shows the user interface configured to accept entryof a cooling utility price level setpoint offset for an enhanced pricingtime period. FIG. 18 shows the user interface displaying a summary ofparameters for an enhanced pricing time period. In this example, for thesake of simplicity and without loss of generality, there is a singleenhanced pricing time period for weekdays from 10:00 am to 7:00 pm. Ingeneral, an arbitrary number of enhanced pricing time periods may bescheduled. FIG. 19 shows the user interface displaying heating 506 andcooling 508 operating setpoints of a utility pricing operating schedule,with offsets applied. For example, during the enhanced pricing timeperiod 510, from 10:00 am to 7:00 pm, the operating setpoints 506, 508are seen to be offset by +5° F. for cooling and −3° F. for heating, perthe parameters set in FIG. 18, and in comparison with the setpoints 502,504 of the nominal schedule shown in FIG. 16. Note that at 5:30 pm(marked at 512), when the nominal schedule changes from “LEAVE” to“RETURN,” the offset operating setpoints 506, 508 change as they follow(with offsets) the changing setpoints 502, 504 of the nominal schedule.

In comparison, FIG. 20 shows another illustrative HVAC controller 600displaying heating and cooling operating setpoints of a utility pricingoperating schedule in a graphical format. In this example, for the sakeof simplicity and without loss of generality, there is a single enhancedpricing time period 610 for weekdays from 10:00 am to 7:00 pm with aheating utility price level setpoint of 55° F. and a cooling utilityprice level setpoint of 90° F. The nominal schedule underlying theutility pricing operating schedule in this example is the same as thenominal schedule of the example of FIGS. 15-19, but during enhancedpricing time period 610, the setpoints of the nominal schedule areirrelevant and overridden by the heating and cooling utility price levelsetpoints (and not merely by an offset).

The present disclosure contemplates further avenues for entering autility pricing schedule into an HVAC controller. An HVAC controller mayinclude a capability for interfacing with information storage media ordevices, such as flash memory devices having any suitable interface,such as Universal Serial Bus (USB), SD and SD variants, and so on. Suchan information storage device may be used to enter a utility pricingschedule into an HVAC controller that is configured to accept theschedule from the device. An information storage device with a utilitypricing schedule could be provided directly from utility, or a utilitypricing schedule could be written to an information storage device by anHVAC system user. The user could, for example, download an electronicfile encoding a utility pricing schedule via an information network suchas the internet to a desktop, laptop, or any other appropriate computeror computing device, then write the file on the local computer to aninformation storage device, such as a flash memory device. Alternately,a computer or computer device may be communicatively connected to anHVAC controller via a wired, wireless, optical, or other type ofconnection, allowing transfer of a utility pricing schedule to the HVACcontroller. Alternately or in addition, the computer could executeapplication code providing a utility pricing schedule editor (which maybe considered an element of the user interface of the HVAC controller)that could write an electronic file encoding a utility pricing scheduleto an information storage device. The utility pricing schedule mayinclude enhanced pricing time periods and utility pricing levelsassociated with the periods. It may or may not further include utilitypricing level setpoints and/or setpoint offsets corresponding to and/orassociated with the utility pricing levels and/or enhance pricing timeperiods.

Methods are contemplated for operating HVAC systems in scenarios whereutilities may enact enhanced pricing time periods of Critical PeakPricing (CPP) on short notice, for example, one day in advance, incontrast with situations when utility pricing schedules may be plannedand communicated well in advance, for example, for seasonal pricing.Users of HVAC systems, such as a homeowners, building superintendents,etc., that are aware of an impending CPP event may make manual inputsvia the user interfaces of HVAC controllers to reduce energy consumptionduring the CPP event.

HVAC controllers such as controllers 300, 500, and 600 of the presentdisclosure may be configured to accept entry of parameters forsingle-occurrence enhanced pricing time periods, similar to theconfigurations disclosed herein for accepting entry of parameters forrecurring enhanced pricing time periods. CPP HVAC control parameters(such as start and end times of the CPP event, setpoints and/or setpointoffsets, and the like) may be entered, used for control of an HVACsystem during a single CPP event, and then discarded (e.g., purged fromcontroller memory). Alternately, one or more sets of parameters forpotential CPP events may be entered into an HVAC controller and storedindefinitely, then activated by user input or other means when an actualCPP event is announced.

It is contemplated that there will be cases in which a utility declaresa CPP event, but users that wish to reduce energy consumption during theevent might not enter or activate CPP HVAC parameters. In such a case,the opportunity to reduce energy consumption during the CPP could belost. However, the present disclosure provides methods and devices thatallow control of an HVAC system by a local HVAC controller according toat least one CPP HVAC control parameter even without explicitintervention by a user. For example, FIG. 21 is a flow diagram of anillustrative method 700 for operating a utility-powered HVAC system,such as system 10 of FIG. 1, which includes predicting a CPP event.

Method 700 includes at block 702 controlling an HVAC unit with a localHVAC controller according to at least one nominal HVAC controlparameter, for example, as in the case of an HVAC system beingcontrolled in accordance with a nominal schedule. At 704, method 700includes recording in a memory of the local HVAC controller at least onemeasure related to an environmental condition of the building. Such atleast one measures may include, for example, an outdoor temperature,humidity, barometric pressure, and/or entropy, as might be recorded byone or more external sensors 40 of HVAC system 10 of FIG. 1. Anotherexample of a measure related to an environmental condition of thebuilding could be a measure of system load, for example, the cycle timeof an air conditioning compressor, the amount of electrical energyconsumed in a time interval, the slope of the inside temperature changeversus time when the air conditioning compressor is active, the slope ofthe inside temperature change versus time when the air conditioningcompressor is inactive, etc. In some illustrative embodiments, themeasure or measures may be recorded twice or more during a time period,which may, for example, allow for a more accurate assessment of theenvironmental condition of the building.

Based at least in part upon the measure(s) related to an environmentalcondition of the building recorded at block 704, at 706, the method 700may include predicting a CPP event of a utility supplying power to thebuilding. Some possible non-limiting examples of how a prediction may bemade including: a prediction of a next-day CPP event may be based on adry-bulb temperature exceeding a threshold on the current day; atemperature trend over several days may indicate an increased likelihoodof a CPP event on the current day; a morning rate of rise in outdoor air(specific) enthalpy may presage an afternoon CPP event.

As part of the prediction process, a first measurement of anenvironmental parameter (such as, for example, an outdoor airtemperature) may be used to forecast a future value for theenvironmental parameter, providing a basis for making a CPP prediction.Historical data of environmental conditions preceding past CPP eventsmay be analyzed to refine prediction rubrics. In general, the method mayallow any suitable prediction logic to be used. An HVAC controller maybe provided with software code to carry out the prediction in anyappropriate way. Such code may be updated over the life of thecontroller, if desired. An installer and/or an HVAC system user mayenter or adjust parameters to tune the predictions of CPP events made bythe HVAC controller. Further, in some illustrative embodiments,predicting a CPP event may include determining a probability value ofoccurrence of the CPP event, and subsequent steps of method 700 may varydepending on the probability value determined.

If a CPP event is predicted at block 706, method 700 may include atblock 708 controlling the HVAC unit with the local HVAC controlleraccording to at least one CPP HVAC control parameter. Controllingaccording to CPP HVAC control parameter(s) results in consuming lessenergy during the CPP event (when rates are elevated) relative tocontrolling according to nominal HVAC control parameter(s). Any suitableCPP HVAC control parameters that result in such reduced energyconsumption may be used. CPP HVAC control parameters may be obtained inany appropriate way. CPP HVAC control parameters may be entered manuallyby a user before or after a prediction of a CPP event. CPP HVAC controlparameters may be modified values of nominal HVAC control parameters, orthey may not have nominal HVAC control parameter analogs. CPP HVACcontrol parameters may include start and end times for a CPP eventenhanced pricing time period and an associated utility pricing levelsetpoint(s) and/or setpoint offset(s), as described herein. Such CPPHVAC control parameters may be used to override, overlay, or modify anominal schedule to result in a utility pricing operating schedule. Insome cases, CPP HVAC control parameters may include parameters relatedto executing HVAC system operation for pre-cooling inside air of thebuilding in advance of the CPP event. In some illustrative embodiments,where a probability value of occurrence of the CPP event is determinedin step 706, a value of one or more CPP HVAC control parameters may beassigned depending at least partially on the determined probabilityvalue of occurrence. This is one way, for example, that the response toan uncertain occurrence of the CPP event may be modulated. The morecertain it is predicted that a CPP event will occur, the more definiteand/or severe the control response of the HVAC system may be. When theoccurrence of a CPP event is less certain, a milder control responsemaybe considered appropriate.

If a CPP event is predicted, method 700 may be extended to communicate aCPP signal to a non-HVAC device. In such a case, the non-HVAC device mayalso reduce energy consumption during the CPP event time period.

Method 700 of FIG. 21 may be extended to accepting a user selection ofwhether or not predictive CPP HVAC system control is desired. The stepat block 708 of controlling the HVAC unit according to CPP HVAC controlparameters would only be executed if a CPP event was predicted and userselection indicated that predictive CPP HVAC system control was desired.Furthermore, in some illustrative embodiments, CPP event overrides maybe selected, in which case control of the HVAC unit may revert tocontrol according to nominal HVAC control parameters (such as accordingto a nominal schedule). A user may manually select a CPP event override(for example, prioritizing comfort in a particular situation over energycost savings), or it may be selected based upon a current measurerelated to an environmental condition of the building. For example, aCPP event may be predicted, but during the time period of the predictedCPP event, milder than anticipated weather conditions may prevail, inwhich case it may be likely that the utility does not execute a CPPevent, and it is then not desired to control according to CPP HVACsystem control parameters.

The disclosure should not be considered limited to the particularexamples described above, but rather should be understood to cover allaspects of the invention as set out in the attached claims. Variousmodifications, equivalent processes, as well as numerous structures towhich the invention can be applicable will be readily apparent to thoseof skill in the art upon review of the instant specification.

1. A method for operating a utility-powered HVAC system for conditioninginside air of a building, the HVAC system having one or more HVAC unitsand a local HVAC controller having a user interface, the methodcomprising: maintaining in a memory of the local HVAC controller anominal schedule, the nominal schedule having a number of days and oneor more time periods for each of at least some of the days, the nominalschedule further having at least one setpoint associated with each ofthe one or more time periods; receiving manual input via the userinterface of the local HVAC controller, the manual input including:accepting entry of a utility pricing schedule that corresponds toscheduled price changes of a utility, including at least one enhancedpricing time period; accepting entry of at least one utility price levelsetpoint offset to correspond to each of the at least one enhancedpricing time periods; modifying or overlaying the nominal schedule toinclude the utility pricing schedule, resulting in a utility pricingoperating schedule; and controlling the one or more HVAC units with thelocal HVAC controller in accordance with the utility pricing operatingschedule.
 2. The method of claim 1, wherein the utility pricing scheduleis provided by the utility and includes at least one recurring enhancedpricing time period.
 3. The method of claim 2, wherein the at least onerecurring enhanced pricing time recurs weekly.
 4. The method of claim 2,wherein the utility pricing schedule includes at least two seasons,wherein the at least one recurring enhanced pricing time periodcorresponds to one of the two seasons.
 5. The method of claim 1, whereinreceiving manual input via the user interface includes accepting entryof a utility price level for each of the scheduled price changes of theutility.
 6. The method of claim 5, further including accepting entry ofat least one utility price level setpoint offset for each of the utilityprice levels.
 7. The method of claim 1, further comprising: acceptingentry of one or more utility price levels associating one of the utilityprice levels with each of the scheduled price changes of the utility;associating at least one utility price level setpoint offset with eachof the utility price levels.
 8. The method of claim 1, wherein theutility pricing operating schedule includes each of the enhanced pricingtime periods such that one of the corresponding utility price levelsetpoint offsets is used to offset one of the setpoints associated withan overlapping time period of the nominal schedule to result in anoperating setpoint used during the overlapping time period.
 9. Themethod of claim 1, wherein the utility pricing operating scheduleincludes a pre-cooling time period.
 10. The method of claim 1, furthercomprising: receiving via the user interface a manual selection ofwhether to enable or disable control in accordance with the utilitypricing operating schedule; and controlling the one or more HVAC unitswith the local HVAC controller in accordance with the nominal scheduleif manual selection to disable control in accordance with the utilitypricing operating schedule is received.
 11. The method of claim 1,wherein the user interface of the local HVAC controller includes adisplay screen and buttons, and wherein the receiving manual input isperformed by a user interacting with the display screen and/or buttons.12. The method of claim 11, wherein the display screen is a touchscreen,and at least one of the buttons is a touchscreen button.
 13. The methodof claim 1, wherein the local HVAC controller is a thermostat.
 14. Amethod for operating a utility-powered HVAC system for conditioninginside air of a building, the HVAC system having one or more HVAC unitsand a thermostat, the method comprising: maintaining in a memory of thethermostat a nominal schedule, the nominal schedule having a number ofdays and one or more time periods for each of at least some of the days,the nominal schedule further having at least one setpoint associatedwith each of the one or more time periods; receiving manual input from auser of the thermostat of a utility pricing schedule that corresponds toscheduled price changes of a utility, wherein the utility pricingschedule includes at least one enhanced pricing time period with acorresponding utility pricing level selected from at least two utilitypricing levels; receiving manual input from the user of the thermostatof at least one utility pricing level setpoint offset to correspond toeach of the at least two utility pricing levels; modifying or overridingthe nominal schedule with the utility pricing schedule to result in autility pricing operating schedule, wherein for each of the at least oneenhanced pricing time periods, the at least one utility pricing levelsetpoint offset that corresponds to the utility pricing level of theenhanced pricing time period is used to offset one of the at least onesetpoints associated with one of the one or more time periods of thenominal schedule to result in an operating setpoint of the utilitypricing operating schedule for the enhanced pricing time period; andcontrolling the one or more HVAC units with the thermostat in accordancewith the utility pricing operating schedule.
 15. The method of claim 14,wherein the utility pricing schedule includes at least one weeklyutility pricing schedule, where the at least one weekly utility pricingschedule includes one or more recurring enhanced pricing time periodsthat recur weekly.
 16. The method of claim 15, wherein the at least oneweekly utility pricing schedule includes one or more weekly groups ofdays, each of the one or more weekly groups of days including one ormore days, further wherein at least one of the one or more recurringenhanced pricing time periods recurs each day of one of the one or moreweekly groups of days.
 17. The method of claim 15, wherein the utilitypricing schedule includes at least two seasons, wherein each of the atleast one weekly utility pricing schedules is associated with one of theat least two seasons.
 18. The method of claim 14, wherein the thermostatincludes a touchscreen, and wherein the receiving manual input can beperformed by a user interacting with the touchscreen.
 19. A thermostatconfigured to operate a utility-powered HVAC system for conditioninginside air of a building, the HVAC system having one or more HVAC units,the thermostat comprising: a user interface configured to receive manualinput from a user of a nominal setpoint schedule, as well as a utilitypricing schedule that corresponds to scheduled price changes of autility; a memory configured to retain the nominal schedule and theutility pricing schedule; and at least one output configured to issueoperational commands to the one or more HVAC units of the HVAC system;wherein the nominal setpoint schedule includes a number of days and oneor more time periods for each of at least some of the days, the nominalschedule further having at least one setpoint associated with each ofthe one or more time periods; wherein the utility pricing scheduleincludes at least one enhanced pricing time period with a correspondingutility pricing level setpoint offset; and wherein the thermostat isconfigured to modify or overlay the nominal setpoint schedule inaccordance with the utility pricing schedule to result in a utilitypricing operating schedule, and to control the one or more HVAC units inaccordance with the utility pricing operating schedule.
 20. Thethermostat of claim 19, wherein the user interface includes atouchscreen, such that manual input can be performed by a userinteracting with the touchscreen.